Any number of vessels require the application of a lining to the interior surface. Such linings are utilized: to provide protection against the deleterious action of caustic, or corrosive, materials; to provide insulation; to prevent the contents of the vessel from coming into direct contact with the interior surface of the vessel; or, to preclude leakage at the juncture of any components that may be required to form the overall vessel. The application of appropriate linings to the interior of these vessels, and particularly those of relatively small diameter, has heretofore been a rather difficult task.
One prior known method has utilized the hand application of sheets of uncured, rubber stock to the interior surface of the vessel and then vulcanizing those hand applied sheets in situ. The vulcanized liner could then be machine ground to obtain the final dimensions. This approach requires splicing, hand buffing, bonding and shrinking operations, and is disadvantageous in view of the need for machining operations, the concomitant need for precision tooling and the resulting costs. Moreover, this method requires long lead times for production, which adversely affects the cost and timeliness of design changes, and it has been found that the liner does, in some instances, separate because of the need to utilize the imprecise hand application of the lining material. Accordingly, the process is labor intensive resulting in high unit costs and a need for a pool of relatively skilled laborers.
U.S. Pat. No. 3,303,079 discloses how to line cylindrical casings, or vessels, with an elastomer by laying calendared sheets of rubber on a mandrel. The elastomer layer is then encased in a resin and filament shell. A curing process is then conducted which produces an elastomer lined, composite vessel. This process is labor intensive and generally requires the hand application of multiple layers of rubber sheet.
U.S. Pat. No. 4,596,619 discloses an apparatus and method for lining a mandrel with an elastomer layer which is covered by a resin and filament coat. The composite body is cured and removed from the mandrel to provide composite shell which may be insertably received within a metallic, tubular vessel. The elastomer layer and the filament layer are applied to the mandrel separately by an applicator roller system which brings the material into contact with the surface to be coated. The coating material is distributed along the surface by moving the applicator roller system relative to the mandrel. This method and apparatus requires synchronization of the linear and circumferential speeds of the applicator relative to the surface of the mandrel. This requires a precise control mechanism and sophisticated electronic circuitry, which is particularly evident when one realizes that the mandrel must be driven by one power source, or drive system, and the applicator roller must be driven by another. Moreover, such apparatus does not permit the lining material to be applied directly to the interior surface of the vessel.
Another prior art system which will permit the lining material to be applied directly to the interior surface of a hollow vessel is the Model 618 Internal Stripwinding Machine originally developed by AMF Corporation and currently available from Steelastic West, Inc. The Model 618 uses a structure very similar to the application roller apparatus disclosed in U.S. Pat. No. 4,596,619. The Model 618 provides a headstock, a boom and a tailstock which supports one end of the boom. The other end of the boom is supported by the headstock. A carriage, carrying the applicator, is movably mounted on the boom. The boom is extended from the headstock into the vessel and then connected with the tailstock. A ribbon of the material to be deposited on the vessel interior is delivered along the boom to the applicator from which it is applied to the vessel. The vessel is rotated by one prime mover and the applicator is moved by another prime mover. The speed of the prime movers must be synchronized, the control system for the synchronization is intricate and expensive to manufacture. The use of at least two prime movers increases the cost of the machine.
While the last two described systems reduce the manual labor, they require considerable investment in capital equipment along with the technical personnel required to operate and repair the intricate electronic and electric systems. It should be appreciated that the aforesaid prior art mechanisms are particularly adapted to the application of a liner to a tubular vessel having a significantly larger inside diameter. The prior art mechanism are, however, totally inapposite for use with tubular vessels of relatively small inside diameters.